Add configurable disk write speed limit for backups (#74)

* Add configurable disk write speed limit for backups

config/config_system.go

@@ -75,6 +75,8 @@ type SystemConfiguration struct {
 	Sftp SftpConfiguration `yaml:"sftp"`
 
 	CrashDetection CrashDetection `yaml:"crash_detection"`
+
+	Backups Backups `yaml:"backups"`
 }
 
 type CrashDetection struct {
@@ -89,6 +91,18 @@ type CrashDetection struct {
 	Timeout int `default:"60" json:"timeout"`
 }
 
+type Backups struct {
+	// WriteLimit imposes a Disk I/O write limit on backups to the disk, this affects all
+	// backup drivers as the archiver must first write the file to the disk in order to
+	// upload it to any external storage provider.
+	//
+	// If the value is less than 1, the write speed is unlimited,
+	// if the value is greater than 0, the write speed is the value in MB/s.
+	//
+	// Defaults to 0 (unlimited)
+	WriteLimit int `default:"0" yaml:"write_limit"`
+}
+
 // Ensures that all of the system directories exist on the system. These directories are
 // created so that only the owner can read the data, and no other users.
 func (sc *SystemConfiguration) ConfigureDirectories() error {

go.mod

@@ -39,6 +39,7 @@ require (
 	github.com/iancoleman/strcase v0.0.0-20191112232945-16388991a334
 	github.com/icza/dyno v0.0.0-20200205103839-49cb13720835
 	github.com/imdario/mergo v0.3.8
+	github.com/juju/ratelimit v1.0.1
 	github.com/karrick/godirwalk v1.16.1
 	github.com/klauspost/compress v1.10.10 // indirect
 	github.com/klauspost/pgzip v1.2.4

go.sum

@@ -275,6 +275,8 @@ github.com/json-iterator/go v1.1.10 h1:Kz6Cvnvv2wGdaG/V8yMvfkmNiXq9Ya2KUv4rouJJr
 github.com/json-iterator/go v1.1.10/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
 github.com/jtolds/gls v4.20.0+incompatible h1:xdiiI2gbIgH/gLH7ADydsJ1uDOEzR8yvV7C0MuV77Wo=
 github.com/jtolds/gls v4.20.0+incompatible/go.mod h1:QJZ7F/aHp+rZTRtaJ1ow/lLfFfVYBRgL+9YlvaHOwJU=
+github.com/juju/ratelimit v1.0.1 h1:+7AIFJVQ0EQgq/K9+0Krm7m530Du7tIz0METWzN0RgY=
+github.com/juju/ratelimit v1.0.1/go.mod h1:qapgC/Gy+xNh9UxzV13HGGl/6UXNN+ct+vwSgWNm/qk=
 github.com/julienschmidt/httprouter v1.2.0 h1:TDTW5Yz1mjftljbcKqRcrYhd4XeOoI98t+9HbQbYf7g=
 github.com/julienschmidt/httprouter v1.2.0/go.mod h1:SYymIcj16QtmaHHD7aYtjjsJG7VTCxuUUipMqKk8s4w=
 github.com/julienschmidt/httprouter v1.3.0/go.mod h1:JR6WtHb+2LUe8TCKY3cZOxFyyO8IZAc4RVcycCCAKdM=

server/backup/archiver.go

@@ -4,8 +4,10 @@ import (
 	"archive/tar"
 	"context"
 	"github.com/apex/log"
+	"github.com/juju/ratelimit"
 	gzip "github.com/klauspost/pgzip"
 	"github.com/pkg/errors"
+	"github.com/pterodactyl/wings/config"
 	"github.com/remeh/sizedwaitgroup"
 	"golang.org/x/sync/errgroup"
 	"io"
@@ -30,13 +32,31 @@ func (a *Archive) Create(dst string, ctx context.Context) error {
 	}
 	defer f.Close()
 
+	// Select a writer based off of the WriteLimit configuration option.
+	var writer io.Writer
+	if writeLimit := config.Get().System.Backups.WriteLimit; writeLimit < 1 {
+		// If there is no write limit, use the file as the writer.
+		writer = f
+	} else {
+		// Token bucket with a capacity of "writeLimit" MiB, adding "writeLimit" MiB/s
+		bucket := ratelimit.NewBucketWithRate(float64(writeLimit)*1024*1024, int64(writeLimit)*1024*1024)
+
+		// Wrap the file writer with the token bucket limiter.
+		writer = ratelimit.Writer(f, bucket)
+	}
+
 	maxCpu := runtime.NumCPU() / 2
 	if maxCpu > 4 {
 		maxCpu = 4
 	}
 
-	gzw, _ := gzip.NewWriterLevel(f, gzip.BestSpeed)
+	gzw, err := gzip.NewWriterLevel(writer, gzip.BestSpeed)
-	_ = gzw.SetConcurrency(1<<20, maxCpu)
+	if err != nil {
+		return errors.WithMessage(err, "failed to create gzip writer")
+	}
+	if err := gzw.SetConcurrency(1<<20, maxCpu); err != nil {
+		return errors.WithMessage(err, "failed to set gzip concurrency")
+	}
 
 	defer gzw.Flush()
 	defer gzw.Close()